1. Field of the Invention
The present invention relates generally to large overhead doors and, more particularly, to an apparatus and to a method of raising and lowering an overhead door. In particular, the present invention is directed to an apparatus and method using a power driven pulley assembly to raise and lower an overhead door.
2. Related Art
By way of background, large overhead doors are utilized in a variety of applications, such as in industrial plants and for airplane hangars. The overhead doors are typically fabricated from a metal frame to form a single planar piece which is covered with a metal or other face material. For example, an apparatus and method of construction of an overhead door is disclosed in Applicant's co-pending U.S. patent application Ser. No. 14/066,003 filed Oct. 29, 2013 which is incorporated herein by reference in its entirety.
The overhead doors are very large, and tend to be relatively heavy. Because the overhead doors are fabricated to form one single piece, they cannot bend at hinges like garage doors that are typically used for housing automobiles. Because the overhead doors are large, heavy and cannot bend, lifting or raising the overhead door proves to be difficult.
Accordingly, it would be desirable to develop an apparatus and a method to raise and lower an overhead door that is able to lift the large overhead door as a single piece.
It is further desirable to develop an apparatus and a method to raise and lower an overhead door that could be adapted to raise and lower nearly any size or configuration of overhead door.
It is further desirable to develop an apparatus and a method to raise and lower an overhead door using a hydraulic cylinder.
It is further desirable to develop an apparatus and a method to raise and lower an overhead door using a pulley system.